Haoyi Chen
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SYSTEMS

Linux CFS Scheduler Extension

Implemented lottery scheduling in the Linux 5.15 kernel and validated it quantitatively in a QEMU-based environment.

Key contributions

  • Modified core Linux 5.15 scheduler sources (fair.c, core.c, sched.h) to implement lottery scheduling, adding new system calls for user-space ticket management
  • Designed a ticket-transfer mechanism to mitigate priority inversion, along with parent-child ticket sharing, a runtime-aging-based SJF approximation, and dynamic priority boosting for I/O-bound tasks
  • Built a QEMU-based kernel test environment for quantitative validation; measured CPU allocation closely matched the theoretical lottery proportions
Title page of the report Enhancement of the Completely Fair SchedulerView PDF →
Project report, 12 pages, in English.